Field of the Invention
The invention generally concerns methods, devices, and systems using an electrode having a CuO/Cu2O array as well as methods, devices, and systems related to continuous flow solar reactors.
Description of Related Art
Hydrocarbons are essential in modern life. Hydrocarbons are used as fuel and raw material in various fields, including the chemical, petrochemical, plastics, and rubber industries. Fossil fuels, such as coal, oil and gas, are composed of hydrocarbons with varying ratios of carbon and hydrogen, and are non-renewably used when combusted, forming carbon dioxide and water. Despite their wide application and high demand, fossil fuels present a number of disadvantages, including the finite reserve, irreversible combustion and contribution to air pollution and global warming. Considering these disadvantages, and the increasing demand for energy, alternative sources of energy are needed.
One potential alternative source is CO2, an actual by-product of fossil fuel combustion. Given that CO2 is a greenhouse gas, using sunlight to convert CO2 to transportation fuel (such as methanol or ethanol) represents a value-added approach to the simultaneous generation of alternative fuels and environmental remediation of carbon emissions from the continued use of conventional fuels.
Selective conversion of CO2 to alcohols like methanol and ethanol and other small organics has several redeeming features especially in light of the fact that large amounts of these chemicals are manufactured worldwide. For example, in the US alone there are eighteen methanol production plants with a cumulative annual capacity of over 2.6 billion gallons. However, the current feedstock for this production is hydrocarbon based with a sizeable carbon footprint. Further, the high operating pressures and temperatures needed for steam reforming translate into correspondingly high capital investment and a long energy pay-back period. Therefore, mild methods for producing methanol, as well as for other alcohols and small organics, from environmentally problematic feedstocks such as CO2 take on added importance.